Healthy Breakfast Casserole
Make this healthy breakfast casserole recipe for the holidays or busy weekday mornings! It's wholesome, hearty and full of fresh flavor.
Updated by Kathryne Taylor on August 29, 2024
Sometimes, you need a healthy make-ahead breakfast. Whether you’re serving a crowd or trying to ease busy weekday mornings, this breakfast casserole is just the ticket.
Typically, breakfast casseroles includes sausage and potatoes. I loaded this one up with fresh veggies and greens instead, including red bell pepper, green onion and spinach.
Creamy feta or goat cheese rounds it all out. You don’t need a ton of dairy to achieve a lovely, luxurious texture. This is a lightened-up dish that seems more indulgent than it really is.
This healthy breakfast casserole is the perfect addition to a holiday breakfast spread. Since it offers some protein and vegetables, it’s a great way to help balance those delicious carb-heavy treats, like muffins and pancakes. I’d be thrilled to find this option alongside bagels and cream cheese. Leftovers are good for lunch, too.
To develop this recipe, I followed my foolproof frittata formula. It’s easy to make, colorful and delicious!
How to Make Breakfast Casserole
You’ll find the full recipe below, but here’s a brief summary:
- Sauté the bell peppers and green onion until tender, then add spinach and cook until wilted. Set the pan aside for a few minutes to cool, so the warm veggies don’t cook the eggs when we stir them together.
- Whisk together the eggs with a dash of full-fat dairy, like whole milk or Greek yogurt, plus some salt and pepper. Stir in half of the cheese (we’re reserving the other half for topping the casserole).
- Transfer the veggies into the egg mixture, stir to combine, then gently pour it all into a buttered baking dish. Top with the rest of the cheese.
- Bake until the eggs are cooked through. That’s it!
How to Prepare This Casserole in Advance
Prepare the mixture as instructed, but refrigerate the egg and veggie mixture in a mixing bowl or in the buttered baking dish for up to two days.
Bake as directed, knowing that your dish may require a few extra minutes in the oven since it’s starting off cold (especially if you refrigerated in the baking dish).
Watch How to Make Healthy Breakfast Casserole
Breakfast Casserole Serving Suggestions
This breakfast casserole would fit in nicely with any breakfast spread. Here are some general suggestions:
- Avocado Toast or any other toast
- Bagels with cream cheese and toppings
- Crispy Hash Browns, which you can make in a skillet while the frittata cooks
- Muffins, pancakes and waffles
- Salads, for an all-around healthy meal
Please let me know how your breakfast casserole turns out in the comments! I love hearing from you.
Healthy Breakfast Casserole
Make this healthy breakfast casserole recipe for the holidays or busy weekday mornings! Featuring red bell peppers, spinach and creamy cheese, this casserole is wholesome, hearty and full of fresh flavor. Recipe yields 8 generous servings.
Ingredients
- 1 tablespoon extra-virgin olive oil
- 2 medium red bell peppers, chopped (about 2 cups)
- ¾ cup thinly sliced green onion (about 1 small bunch)
- 5 ounces roughly chopped spinach (about 5 cups)
- 12 eggs
- 3 tablespoons full-fat dairy (heavy cream, half-and-half, whole milk, sour cream or yogurt)
- Several dashes of your favorite hot sauce, like Cholula
- ½ teaspoon fine salt
- 10 twists of freshly ground black pepper
- 4 ounces (1 cup) crumbled feta or goat cheese
Instructions
- Preheat the oven to 350 degrees Fahrenheit. Grease a 9 by 13-inch pan with butter (don’t be tempted to use cooking spray; it doesn’t work nearly as well).
- In a large skillet, warm the olive oil over medium heat until shimmering. Add the bell pepper and green onion and cook until the pepper is tender and cooked through, about 8 to 10 minutes.
- Add the spinach to the skillet and cook, while stirring, until wilted, about 2 minutes. Set the pan aside to cool for a bit while we prepare the egg mixture.
- Crack the eggs into a medium mixing bowl. Add your dairy of choice, several dashes of hot sauce, plus the salt and pepper. Whisk just until the egg yolks and whites are blended.
- Stir in half of the cheese (we’re reserving the other half for topping the frittata before baking). Transfer the lightly cooled veggies into the bowl, and stir to combine.
- Pour the mixture into the prepared pan. Evenly disperse the remaining cheese on top.
- Bake for 25 to 35 minutes (keep an eye on it), until the eggs are puffed and appear cooked, and the center of the frittata just barely jiggles when you give it a gentle shimmy. For good measure, insert a fork about ¼-inch into the center of the eggs and make sure the fork comes out clean
- Place the frittata on a cooling rack until you’re ready to serve. Slice with a sharp knife, and serve. Leftovers will keep well for about four days in the refrigerator. Enjoy leftovers chilled, at room temperature, or gently reheat in the microwave or oven.
Notes
Prepare in advance: Cover and refrigerate the mixture until you’re ready to bake (it should keep well for up to two days). Bake as directed, but know that your dish may require a few extra minutes in the oven since it’s starting off cold.
Change it up: I love the flavors you see here, but you can definitely use other vegetables in similar quantities. More hardy greens like kale or chard will require a bit more cooking time. Find other flavor variations on my frittata post.
Can I freeze it? I don’t recommend freezing leftover breakfast casserole. When I defrosted my frozen slices, they turned very watery and slightly rubbery. If you’re looking for a good egg-based freezer recipe, check out my breakfast burritos.
Nutrition
The information shown is an estimate provided by an online nutrition calculator. It should not be considered a substitute for a professional nutritionist’s advice. See our full nutrition disclosure here.
Absolutely perfect! I only had frozen bell peppers mix with carrots and frozen spinach and it worked out perfectly. You cannot tell at all and the taste is reminiscent of the Starbucks egg bites – feta was a great choice.
I’m glad you enjoyed it! Thank you for your review, K.
Hey did you bother sautéing the frozen vegetables, or did you just bake them frozen?
I sautéed them :) I wanted to get the extra moisture out of them
I’ve tried both ways now and totally agree, sautéing works way better at least for the peppers. I didn’t see a difference in the greens, but the peppers felt a little slimy when I baked them straight from frozen – not great! Sautéing made a huge difference
Just made this for dinner (along with a nice salad), with the idea of serving it on Christmas morning, and loved it! It was super easy, delicious, and the fact we can make it a day ahead makes this a winner! I used feta and a bit of Parmesan cheese that I had in the fridge, but will work well with goat cheese for my “cow cheese intolerant” family members.
This would be a great recipe for Christmas morning! I’m glad you loved it. Thank you for sharing, Barbara.
Oh the places this recipe can go! It’s FANTASTIC exactly as is, but if you have some stuff in the fridge in need of using, this casserole might be able to help. Think mushrooms, jalapeno pepper, broccoli, leftover ham, or sausage… so many possibilities.
I used gruyere cheese but mozz would work well as another reviewer suggested, and so would cheddar.
Best thing is, it tastes even better heated up the next day (if you’re lucky enough to have some left over). The flavor blends are amazing!
Awesome recipe! Total keeper!
Thank you for sharing, Tracy.
If I add ciabatta bread to make a strata should I use the same amount of milk?
Hi Amy, I haven’t tried it so I can’t say for sure. Sorry!
Delicious! I made this today for Christmas Eve brunch. I did sprinkle a bit of mozzarella in it as well. Will be making again.
That’s great to hear, Megan!
Kate I made this today for breakfast for family we were visiting. Made it the night before for the convenience of just having to stick it in the oven the next morning. This was a hit! Everyone raved about it. So easy to prepare too. Thank you for another awesome recipe! Merry Christmas to you too!
I love this recipe. I used red chard instead of spinach, sauteing the stems with the onions and adding the leaves later. I also used marscaone instead of the feta and dairy which made the casserole super moist. I also sprinkled cheddar on top. This is now my go to breakfast casserole!
Sounds delicious! I like how you got creative.
love this recipe! So, being a vegan I substituted the eggs for Tofu crumbled up, and used Turmeric for flavor and yellow coloring. Turned out delicious!
Made last night and warmed for breakfast this morning. LOVED IT!! Always looking for new ideas for breakfast as husband is GF and he hates the bread and cereals. Dos glad i found you, going to make the no bake granola bars today. Thanks so much for the recipes
Great, Chris! I’m happy you enjoyed it.
I make this all the time. Love how adaptable it is to whatever veggies I have on hand. Thanks for your website. I make so many of your recipes all the time. I think I’ve bought 4 copies of your book since I keep giving it away lol.
I’m glad you love it, Amy! Thank you for sharing my book. :)
Oh my gosh. I made this today, only change was adding a red onion instead of green onion and swapping one of the red peppers for a yellow pepper. Soo good!! Definitely putting this in our rotation.
That’s great to hear, Sarah! Thanks for your review.
I’m wondering if anyone has tried this in muffin cups. If so how long did they cook?
Delicious! This is better than your average egg casserole. I followed instructions exactly (except one of my bell peppers was yellow, and I did use nonstick spray even though I knew I shouldn’t), and everyone loved it. Simple enough for a weeknight breakfast-for-dinner and I will make it again!
That’s great to hear, Liz! I appreciate your review.
I’m planning to make the 2X scale version and I see that egg quantity is the only ingredient amount that changes. Is that correct? Will this amount still work in a 9×13 pan? Any adjustment to cook time? Thanks!
Hi Denise, Yes, it doesn’t seem to impact the directions. You may want to divide into two pans to reduce cooking time. Just switch the dishes halfway through.
This looks sooo good, and I’d like to make this for the upcoming week. However, I am wondering for how many days I can keep it in the fridge? Will it last a couple of days?
Hi Rebecca is should last 3-4 days, but use your best judgement!
We made this for a toddler breakfast birthday party, and it was a HIT. The only modification we made was adding about 1/3-1/2 loaf of sourdough cubed and placed in the bottom of the pan before pouring the egg mixture over. We adjusted the time accordingly (about 50-55 mins at 350), and it was awesome! Will 100% make again!
Would it work to substitute asparagus for the spinach?
Hi Pam, you could try it. I would be sure to cook your asparagus first. Let me know what you think!
Have you ever tried cooking this in a crockpot? Do you think it would turn out or do you have any recommendations for giving it a try? Thanks so much! I love your blog.
I haven’t, sorry! I recommend this as written. I hope you try it!
Thanks for the tip on preparing this recipe in advance. Some of us (me) weren’t aware that we could do that! I greatly appreciate tips about advance preparation and cooking for a crowd!
This was a hit. Made it just the way it was written and it dissapeared. Happy to have an egg dish without bread.
I’m glad you enjoyed it, Caro! I appreciate your review.
Would like to make this for two people and avoid leftover. Any recommendations on scaling down? Can I just half everything or would that not work. Smaller baking dish?
Hi! You could cut the recipe in half and put it in a smaller baking dish. You may need less time so keep an eye on it.
Ohhhh! We have family visiting and this will be perfect for breakfast. Thinking about adding Impossible Sausage to it. Making my market list now. All of your recipes are ALWAYS a hit!!!
Kate I’m a big fan of your recipes!
I’m wondering if this recipe could be made as egg bites in a muffin pan for a bridal shower brunch.
Hi! I would follow my How to Make Frittatas (Stovetop or Baked) with the muffin tin for guidance. Enjoy!
Any suggestions for dairy free? I am not a fan of many df cheeses. Other ideas?
Hi, you can omit the cheese and use a thicker dairy free milk.
Made this to take to a friend’s house for breakfast and it was delicious. I also made it the night before and took it out of the frig to start to come to room temperature and then baked it – took about 5 mins longer. I added some broccoli and mushrooms and didn’t have enough to feta so I put sharp cheddar in the mixture and then feta on top. It was a hit!
Thank you for sharing how you made this, Leslie! I appreciate your review.
Best baked egg recipe out there – I make it regularly and divide up for my lunch for the week. Reheats great!
Love to hear that, Kristin! Thank you for your review.
My husband and I really enjoyed this recipe. I halved the recipe since I was only making it for 2 people and baked it in a 8×8 dish. It took 25 minutes at 350 degrees. I also added mushrooms. I was nervous about halving the recipe, but it turned out perfect! I served it with toast and a fruit bowl. I will definitely make this again!
Thank you for sharing how you made it, Holly!
Thanks, great work on the how-to-guide here.
Hello,
Is this Frittata baked in a 9×13 pan? It says only 8 servings but maybe the portions are generous? Thanks
Hi! Yes, this is baked in a 9×13 pan. Its not quite as thick so the slices are bigger. If that helps?
Super easy and delicious! One of the healthiest egg casseroles I’ve found that still tastes amazing. I make it for breakfast or combine with a salad for lunch.
Another go-to Cookie and Kate recipe!
Great to hear, J!
Made this for dinner tonight. Had roasted red peppers and pickled onions in hand, as well bok choy. I love casseroles for dinner
I’m excited you enjoyed it, Susan! Thank you for your review.
Can you make this recipe in muffin tins instead of a casserole?
Hi! See my How to Make Frittatas (Stovetop or Baked) for guidance.
I have made this so many times, love it! I’ve tried half eggs/half egg whites (works!) plain greek yogurt or whole milk (prefer the yogurt) and always add a handful of cherry tomatoes cut in half. Yum! It is consistently amazing. Thank you for my go to recipe!
Great to hear, Dianne! I appreciate your review.
Approximately how much cooked meat, such as Mexican chorizo, pork sausage, ham, bacon, etc. do you think would be appropriate without overloading the recipe?
I’m not sure since I’m a vegetarian. Sorry!
Never made breakfast casserole before but I Trying to find healthy breakfast options for my pregnant daughter. I was surprised how easy it was to make and delicious!
That’s great to hear, Angela!
If I prepare this recipe in advance (including baking) to be portioned and used for breakfast or lunch for the week should I undercook it a bit? Will that work?
I recommend cooking as instructed for best results and food safety.
I have made this many times but just getting out of the hospital after a long Covid pneumonia stay, I am shocked how swarmed your site is with ads flying in and out constantly. I could hardly read the recipe and they would even kick me off the site!!! Very poor quality cooking site now!!!
I just made this and it was delish and very easy! TJs was out of green onion so I left that out, used chalula, feta and sour cream. I served with a little sour cream too and used 6 oz of spinach. Was done right at 25 minutes and was great. Next time I might broil it for a minute to brown the top. It’s such a great recipe because it’s so versatile. I can imagine making with sautéed onions, cooked broccoli, Brussels sprouts, etc. thanks for a yummy recipe!
That sounds delicious, Gretchen! Thank you for your review.
I made this recipe several times in a lasagna pan and it was great. Can the same recipe be used to make breakfast muffins?
Sure! I would follow my How to Make Frittatas (Stovetop or Baked) suggestions.
Your recipes are always winners. I’d like to make this for Easter brunch but one guest can’t tolerate peppers. Any suggestions for alternative? Maybe mushrooms? Thanks!
Hi! You can omit them. Carrots could be nice. I hope it’s a hit!
Thanks Kate. Carrots is a great idea! Yum.
This s absolutely delicious! I made three casseroles with cheese, spinach, and bell peppers for breakfast at my church. Everyone loved them and none was left. Making this recipe again as part of our Mother’s Day Brunch. Super easy and pretty quick.
This looks great, but wow! Is one serving really 97% of recommended daily intake? Yikes!
Oh my gosh, I hunted and hunted for your recipe! I made it twice around the holidays and was tapped to help with the choir breakfast tomorrow. I feel like I’ve won a prize for finding this recipe in time! Both times I have made this and added a package of the precooked turkey breakfast sausages which I chop before adding. I was short on spinach but found a good balance with the other veggies and sharp cheddar cheese. Excellent flavor and texture and we enjoyed it at room temp. I used heavy cream as the dairy.
Thank you for sharing, KR!
This is a fantastic recipe! Made exactly as the recipe was written and it turned out lovely. Will be making this for years to come! Thank you!
You’re welcome, S!
So glad you shared this wonderful recipe!!!!
I’m so excited to find you have a recipe for this! Any chance you have guidance on how to turn it into a finger-friendly breakfast food for a party like as egg or casserole bites/muffins? Truly love your recipes and how I can always trust them.
You can try cooking it in a muffin tin. Follow my How to Make Frittatas.
Thank you! Didn’t see that recipe!
Delicious. Made it exactly as written. Used sliced goat cheese from Trader Joe’s and cut it into small pieces. Used low fat sour cream because that’s what I had.
Thank you for sharing, Stacy!
We enjoyed this recipe, which has a lot of great stuff all in one place, but thanks particularly for the tip about using butter instead of oil spray! I’ve used it now for similar egg dishes I make as well as this and it’s miraculous in stopping egg from sticking to the dish.
Such a great recipe, Kate. My book club let it fuel our long session of picking titles for the upcoming year! Now I’ll add it to my rotation…so many of yours on it already (and I have your cookbook)! Thanks.